When your body temperature drops, your heart, nervous system and other organs cannot work correctly.Left untreated, hypothermia eventually leads to complete failure of your heart and respiratory system and to death.

Hypothermia is most often caused by exposure to cold weather or immersion in a cold body of water.Primary treatments are methods to warm the body back to a normal temperature.Source: http://www.mayoclinic.com/health/hypothermia/DS00333 (downloaded: October 31, 2010)

So what does this have to do with you and sailing at Canyon Lake? Below is a chart of the average surface water temperature at Canyon Lake. As you can see, there is a wide variance of water temperature between summer swimming season and mid winter.

Mild...core temperature 35 to 34 degrees Celsius (95 to 93.2 F)+ uncontrolled intense shivering occurs+ movements become less coordinated. Unable to grasp a line or ladder at this point.+ judgment capability impaired, but is still alert+ feelings of intense coldness such as numbness in hands and feet

Treatment + remove from elements if able+ remove wet clothing...handle the person gently as jolting can affect heart function by pumping back cold blood to the heart.+ avoid massaging the muscles as this will also send cold blood back to the heart. It will result in further core temperature drops or heart standstill.+ layer on clothing. Cover the head and neck well!+ apply lukewarm objects such as chemical packs, water bottles or hand warmers to the head, neck and trunk. Watch for signs of burns. The temperature of these objects should be tested on your elbow before application.+ if person is able to swallow and is conscious, give warm, non alcoholic drinks such as milk or soup. Avoid coffee, tea and cocoa as these are cardiac stimulants. Avoid alcohol as it dilates blood vessels causing further heat loss. So much for the Saint Bernard dog and the rum barrel wrapped around his neck!

Moderate...core temperature 33 to 31 degrees Celsius(91.4 to 87.8 F)+ shivering slows or stops. The body's initial compensating response to cold is to shiver uncontrollably. This generates heat by the involuntary muscular movement. When this fails, the body stops shivering because it uses up more energy...hence heat to cause the muscle to shiver. It is a sign the person is in serious trouble!+ muscles begin to stiffen+ speech is slow, vague, slurred+ mental confusion and apathy is present+ drowsiness and strange behaviour occurs+ breathing is slower and more shallow

Treatment+ As above ...with mild stage+ monitor vital signs and be ready to start CPR. If there is a pulse and breathing....no matter how faint...do not give CPR. Keep a VERY CLOSE watch!+ skin to skin such as person to person contact is imperative. Once the person has stopped to shivering, they are unable to get warm again without an external heat source.

Severe... core temperature less than 31 degrees Celsius(86 F and less)+ skin cold and bluish + eyes may be dilated+ marked lack of coordination+ may show signs of clouded consciousness or may become unconscious.+ person may appear DEAD, especially with cold waxy skin and dilated pupils. NEVER assume a person is dead until the body has been rewarmed.

Treatment+ Skin to skin contact in areas of chest and neck. Keep head covered. A prewarmed sleeping bag with one or two naked people in it is very functional.+ exhale warm air near the person's nose and mouth or introduce warm steam into the area.+ use mild heat... stop any further temperature loss.+ if the person is semi conscious, keep the person awake. He/she is in serious trouble and needs close and continuous monitoring. HANDLE VERY GENTLY! By now the heart is extremely sensitive. Again, DO NOT MASSAGE THE MUSCLES. REWARM SLOWLY!+ if the person is unconscious check the carotid pulses. Take a full two minutes and check each side if unable to palpate initially on one side. Check the breathing. If no pulse or breathing is present , then start CPR. Always assume that this person's situation is reversible. DO NOT GIVE UP! The person is considered to be in a "metabolic ice box"! Continue CPR until the person has been rewarmed and the heart begins to beat, or the person applying CPR cannot continue without endangering themselves, or the person has been rewarmed and the heart does not begin to beat.+ medical help is imperative...hospitalization is needed

Stage 2: Functional Disability (2-30 minutes): "If you survivethe cold-shock reflexes after falling overboard, cold water can stillaffect you in other ways...Your hands get cold quickly and you lose manualdexterity and grip strength. This can affect your ability to graspa rescue line or life ring or even to help pull yourself back aboardyour vessel. Both swimming failure and loss of manual dexteritycan occur during the first 30 minutes after falling into cold water.Again, a PFD would be life-saving during this period, as it woulddramatically decrease your need to swim to keep your head up."

Stage 3: Hypothermia(> 30 minutes):"Hypothermia is a decreasein the body’s core temperature (i.e., a drop in the temperature ofthe body’s vital organs below 95°F) resulting from excessive heatloss to the cold water. Hypothermia is not really a threat untilyou have been immersed in cold water for at least 30 minutes...When the body’s temperature falls to around 86-90°F, you willlose consciousness and likely drown."

Stage 4: Post-Rescue Collapse(> 30 minutes): "A survivor is stillat significant risk even after removal from the water. Significantlevels of hypothermia can slow the body’s normal defenses againsta sudden drop in blood pressure...This can occur when the survivoris removed from the water, particularly if he/she is rescued in avertical posture and not promptly placed in a horizontal posture..."

A well fitting life jacket (PFD) worn over layered clothing is your best protection against hypothermia and drowning.

You've accidentally fallen into the water in mid-winter, there are other boaters nearby but they don't see your plight. With this whistle attached to your life jacket, you'll get their attention!

An important step in treating hypothermia is to prevent further heat loss. Be prepared! Keep a thermal blanket on your boat for emergencies.

Break through in cold water drowning search and rescue (SARbot).

Photo source: : Seabotics.com"Golden HourMedical research and studies have proven that people can survive near drowning without permanent damage. Essentially the theory revolves around colder water rescues (less than 21ºC/69.8ºF) where the person is recovered from the water in under 60 minutes. Some have shown that the amount of time could reach 90 minutes. It does vary from person to person. The rescued victim is not resuscitated immediately, but over a period of approximately 48 hours."Source: Seabotics.com

"... When an unconscious body sinks below 15 feet, water pressure can hold it down forever. The SARbot could discover human remains that have long been missing...

Things get very bad, very quickly for people in cold water. Just minutes after total submersion, heart and brain activity stop. But the cold also protects. If rescuers can reach a drowning victim in less than 90 minutes, it’s possible to resuscitate, often with no long-term ill effects. Inspired by this fact, Duncan Winsbury, a former station manager at the Fire & Rescue Service in Derbyshire, England, set out to build a robot that could find and retrieve cold-water drowning victims fast.

Winsbury explained his vision to Jesse Rodocker, the co-founder of Seattle robot-maker SeaBotix, and the duo made SARbot, upgrading a shoebox-size remotely operated sub typically used to salvage shipwrecks. The robot transmits sonar and video data to land via a cable. Rescuers then can use its arm to latch onto a victim and haul both him and the ’bot in like a lobster trap.

SARbot is simple enough that trained rescuers can get it in the water in four minutes. In tests last year, it found practice dummies less than five minutes after hitting the water. “Only a few fire departments carried the jaws of life when it debuted,” Rodocker says. “Now they’re on nearly every truck. SARbot could have a similar impact.”

Impressed by SARbot’s performance, U.K. officials have showninterest in purchasing a fleet, as have officials in Seattle and Chicago. “This can help cut drowning deaths in half,” Winsbury says. “And we never have to get our feet wet.”" source: Popular Science online

Video shot by SMART diver on June 26, 2011 while searching for drowning victim at Canyon Lake, Texas.